1. 1. I. Zugravescu and M. Petrovanu, N-ylide Chemistry (McGraw-Hill, London, 1976).
2. 2. M.V. Tri, PhD Thesis, Researches for obtaining new pyridazinium ylides ("Alexandru Ioan Cuza" Univ., Faculty of Chemistry, 1976).
3. 3. D.O. Dorohoi, D.H. Partenie, L.M. Chiran, and C. Anton, J. Chim. Phys. Phys.-Chim. Biol. 91, 419 (1994).
4. 4. Y. Kazarzi and G. Surpateanu, Heterocycles 51, 863 (1999).
5. 5. M. Petrovanu and I. Zugravescu, Cycloaddition Reactions (Acad. Press, Bucharest, 1987).